<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Demo1</title>
</head>
<body>
    <h1>Hello HTML!</h1>
    <h1>this is h1</h1>
    <h2>this is h2</h2>
    <h3>this is h3</h3>
    <h4>this is h3</h4>
    <h5>this is h3</h5>
    <h6>this is h3</h6>

</body>
</html>